1. A NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 350 MILESSOUTHWEST OF BERMUDA IS PRODUCING A LARGE AREA OF GALE-FORCEWINDS OVER THE WEST-CENTRAL ATLANTIC. ALTHOUGH THE ASSOCIATEDSHOWERS AND THUNDERSTORMS ARE CURRENTLY DISORGANIZED...THE LOWCOULD GRADUALLY ACQUIRE SUBTROPICAL CHARACTERISTICS AS IT MOVESOVER WARMER WATER DURING THE NEXT COUPLE OF DAYS. THIS SYSTEM HASA LOW CHANCE...10 PERCENT...OF BECOMING A SUBTROPICAL CYCLONEDURING THE NEXT 48 HOURS AS IT DRIFTS GENERALLY SOUTHWARD.ADDITIONAL INFORMATION ON THIS GALE AREA CAN BE FOUND IN HIGH SEASFORECASTS ISSUED BY THE NOAA NATIONAL WEATHER SERVICE UNDER AWIPSHEADER NFDHSFAT1...AND UNDER WMO HEADER FZNT01 KWBC.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THENEXT 48 HOURS.

Thanks Ron! I saw it had a 10% chance, but didn't even think to check the ATCF with it being so low.

Just might see a subtropical system outta this one, the visible sat shows a pretty good low spinning out there! And even if it doesn't develop, the SE coastline could get some strong easterly wind and surf from it. It's quite windy in Miami right now as it is!

1. A NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 400 MILESSOUTHWEST OF BERMUDA IS PRODUCING GALE FORCE WINDS OVER AN AREAEXTENDING SEVERAL HUNDRED MILES TO THE NORTH OF THE CENTER. THEASSOCIATED SHOWERS AND THUNDERSTORMS HAVE BECOME A LITTLE BETTERORGANIZED OVERNIGHT...AND THE LOW COULD ACQUIRE SUBTROPICALCHARACTERISTICS OVER THE NEXT DAY OR TWO. THIS SYSTEM HAS A MEDIUMCHANCE...40 PERCENT...OF BECOMING A SUBTROPICAL CYCLONE DURING THENEXT 48 HOURS AS IT MOVES SLOWLY WESTWARD TODAY AND NORTHWESTWARDON TUESDAY. ADDITIONAL INFORMATION ON THIS GALE AREA CAN BE FOUNDIN HIGH SEAS FORECASTS ISSUED BY THE NOAA NATIONAL WEATHER SERVICEUNDER AWIPS HEADER NFDHSFAT1...AND UNDER WMO HEADER FZNT01 KWBC.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THENEXT 48 HOURS.

1. A NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 425 MILESSOUTHWEST OF BERMUDA CONTINUES TO PRODUCE GALE FORCE WINDS OVER ANAREA EXTENDING SEVERAL HUNDRED MILES TO THE NORTH OF THE CENTER. THE ASSOCIATED SHOWERS AND THUNDERSTORMS CONTINUE TO SHOW SIGNS OFORGANIZATION...AND THE LOW COULD ACQUIRE SUBTROPICALCHARACTERISTICS TONIGHT OR ON TUESDAY. THIS SYSTEM HAS A HIGHCHANCE...60 PERCENT...OF BECOMING A SUBTROPICAL CYCLONE DURING THENEXT 48 HOURS AS IT MOVES SLOWLY WESTWARD TODAY AND NORTHWESTWARDON TUESDAY. ADDITIONAL INFORMATION ON THIS GALE AREA CAN BE FOUNDIN HIGH SEAS FORECASTS ISSUED BY THE NOAA NATIONAL WEATHER SERVICEUNDER AWIPS HEADER NFDHSFAT1...AND UNDER WMO HEADER FZNT01 KWBC.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THENEXT 48 HOURS.

1. A NON-TROPICAL LOW PRESSURE SYSTEM LOCATED ABOUT 435 MILES SOUTHWESTOF BERMUDA CONTINUES TO PRODUCE GALE FORCE WINDS OVER AN AREAEXTENDING SEVERAL HUNDRED MILES TO THE NORTH AND WEST OF THECENTER. SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH THIS LOWHAS CHANGED LITTLE OVER THE PAST FEW HOURS...AND THIS SYSTEM STILLHAS SOME FRONTAL CHARACTERISTICS. HOWEVER...CONDITIONS APPEARCONDUCIVE FOR THIS LOW TO GRADUALLY ACQUIRE SUBTROPICALCHARACTERISTICS TONIGHT OR TUESDAY. THIS SYSTEM HAS A HIGHCHANCE...70 PERCENT...OF BECOMING A SUBTROPICAL CYCLONE DURING THENEXT 48 HOURS AS IT MOVES SLOWLY WESTWARD TONIGHT AND MOVESNORTHWESTWARD ON TUESDAY. ADDITIONAL INFORMATION ON THIS GALE AREACAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NOAA NATIONALWEATHER SERVICE UNDER AWIPS HEADER NFDHSFAT1...AND UNDER WMO HEADERFZNT01 KWBC.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THENEXT 48 HOURS.

INTERESTS IN BERMUDA SHOULD MONITOR PRODUCTS ISSUED BY THE BERMUDAWEATHER SERVICE.

DISCUSSION AND 48-HOUR OUTLOOK------------------------------AT 200 PM AST...1800 UTC...THE CENTER OF TROPICAL STORM SEAN WASLOCATED NEAR LATITUDE 27.7 NORTH...LONGITUDE 69.5 WEST. SEAN HASBEEN NEARLY STATIONARY DURING THE PAST SEVERAL HOURS...BUT A SLOWMOTION TOWARD THE WEST-NORTHWEST IS EXPECTED TO BEGIN LATER TODAY. A TURN TOWARD THE NORTHWEST IS FORECAST BY WEDNESDAY...WITH A TURNTOWARD THE NORTH LIKELY ON THURSDAY.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 45 MPH...75 KM/H...WITH HIGHERGUSTS. SOME INCREASE IN STRENGTH IS POSSIBLE DURING THE NEXT 48HOURS.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 380 MILES...610KM...PRIMARILY TO THE NORTH OF THE CENTER.

SURF...SWELLS GENERATED BY SEAN ARE EXPECTED TO AFFECT PORTIONS OFTHE SOUTHEASTERN COAST OF THE UNITED STATES DURING THE NEXT COUPLEOF DAYS. THESE SWELLS WILL CAUSE LIFE-THREATENING SURF AND RIPCURRENTS. PLEASE SEE STATEMENTS FROM YOUR LOCAL NATIONAL WEATHERSERVICE OFFICE FOR MORE DETAILS.

MAXIMUM SUSTAINED WINDS ARE NEAR 50 MPH...85 KM/H...WITH HIGHERGUSTS. SOME STRENGTHENING IS POSSIBLE OVER THE NEXT COUPLE OFDAYS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 265 MILES...425KM...MAINLY TO THE NORTH OF THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB...29.50 INCHES.

HAZARDS AFFECTING LAND----------------------WIND...TROPICAL STORM CONDITIONS ARE POSSIBLE ON BERMUDA LATETHURSDAY OR EARLY FRIDAY.

SURF...SWELLS GENERATED BY SEAN ARE EXPECTED TO AFFECT PORTIONS OFTHE SOUTHEASTERN COAST OF THE UNITED STATES DURING THE NEXT COUPLEOF DAYS...CAUSING LIFE-THREATENING SURF AND RIP CURRENTS. PLEASESEE STATEMENTS FROM YOUR LOCAL NATIONAL WEATHER SERVICE OFFICE FORMORE DETAILS.

RAINFALL...SEAN IS EXPECTED TO PRODUCE 1 TO 3 INCHES OF RAIN ONBERMUDA.

SURF...SWELLS GENERATED BY SEAN ARE EXPECTED TO AFFECT PORTIONS OFTHE SOUTHEASTERN COAST OF THE UNITED STATES AND BERMUDA DURING THENEXT COUPLE OF DAYS...CAUSING LIFE-THREATENING SURF AND RIPCURRENTS. PLEASE SEE STATEMENTS FROM YOUR LOCAL NATIONAL WEATHERSERVICE OFFICE FOR MORE DETAILS.

DURING THE PAST FEW HOURS...CONVECTION HAS BECOME BETTER ORGANIZEDIN A BROKEN RING AROUND THE CENTER OF SEAN...WITH THE POSSIBILITYTHAT AN EYE FEATURE IS FORMING. SUBJECTIVE SATELLITE INTENSITYESTIMATES FROM TAFB/SAB ARE 45/55 KT...AND A BLEND OF THESE DATAGIVES AN INITIAL WIND SPEED OF 50 KT. SEAN HAS ABOUT 24 TO 36HOURS OF RELATIVELY LOW SHEAR CONDITIONS...WHICH WOULD SEEM TOFAVOR SOME INTENSIFICATION. MODEL GUIDANCE IS A BIT HIGHER...ANDTHE OFFICIAL WIND SPEED FORECAST IS RAISED FROM THE LAST ONE...BETWEEN THE STATISTICAL MODELS AND THE INTENSITY CONSENSUS. THEOFFICIAL FORECAST MIGHT BE CONSERVATIVE IF A CENTRAL CORE BECOMESWELL ESTABLISHED.

THE GRADUAL POLEWARD TURN OF THE CYCLONE HAS BEGUN...WITH ANINITIAL MOTION ESTIMATE OF 320/3. SHORTWAVE RIDGING OVER THEWESTERN ATLANTIC WILL MOVE TO THE EAST LATER TODAY...STEERING SEANON A PATH TOWARD THE NORTH AND NORTH-NORTHEAST BY EARLY TOMORROW. AS A TROUGH OVER THE EASTERN UNITED STATES APPROACHES THESTORM...AN INCREASE IN MID-TROPOSPHERIC FLOW SHOULD CAUSE THETROPICAL CYCLONE TO ACCELERATE NORTHEASTWARD. THERE CONTINUES TOBE A FAIR AMOUNT OF SPREAD...HOWEVER...ON HOW FAR SEAN MOVES FROMBERMUDA. THE GFS AND ECMWF HAVE BEEN MORE CONSISTENT THAN THE RESTOF THE GUIDANCE SHOWING A CLOSER TRACK TO BERMUDA...SO THE OFFICIALFORECAST WILL STAY NEAR THOSE HISTORICALLY RELIABLE MODELS. MOST OFTHE GLOBAL MODELS SHOW THIS SYSTEM BEING ABSORBED WITHIN A FRONTBETWEEN DAY 3 AND DAY 4...AND THE NHC FORECAST CONTINUES TO FOLLOWTHIS SCENARIO.

RAINFALL...SEAN IS EXPECTED TO PRODUCE 1 TO 3 INCHES OF RAIN ONBERMUDA.

SURF...SWELLS GENERATED BY SEAN ARE AFFECTING PORTIONS OF THESOUTHEASTERN COAST OF THE UNITED STATES AND BERMUDA...CAUSINGLIFE-THREATENING SURF AND RIP CURRENTS. PLEASE SEE STATEMENTS FROMYOUR LOCAL NATIONAL WEATHER SERVICE OFFICE FOR MORE DETAILS.

SATELLITE IMAGERY INDICATES THAT SEAN IS STRENGTHENING. THE CLOUDPATTERN CONSISTS OF A LARGE COILED BAND...WHICH APPEARS TO BEWRAPPING UP INTO A BANDING EYE FEATURE. DVORAK ESTIMATES ARE 55 KTFROM BOTH TAFB/SAB...SO THIS WILL BE THE INITIAL WIND SPEED. WITHTHE DEVELOPMENT OF THE CENTRAL CORE AND ABOUT A DAY OF LIGHT SHEARCONDITIONS REMAINING...FURTHER INTENSIFICATION SEEMS PROBABLE. ITIS A LITTLE PUZZLING WHY NONE OF THE MODELS MAKE THIS A HURRICANE...ALTHOUGH THE INTENSITY GUIDANCE HAS GENERALLY HAD A LOW BIAS WITHTHIS SYSTEM. GIVEN THE DEVELOPING EYE FEATURE...THE NEW NHCFORECAST SHOWS SEAN REACHING HURRICANE STRENGTH...WHICH IS A BITHIGHER THAN THE SHIPS/LGEM MODELS.

THE STORM HAS TURNED TOWARD THE NORTH AT ABOUT 5 KT...A LITTLEFASTER THAN EARLIER. A GRADUAL TURN TOWARD THE NORTHEAST WITH SOMEACCELERATION IS EXPECTED TOMORROW AS THE TROPICAL CYCLONE FEELS THEINFLUENCE OF A TROUGH MOVING INTO THE EASTERN UNITED STATES.ALTHOUGH THERE IS STILL SOME SPREAD...THE GUIDANCE IS PRETTYCONSISTENT IN SHOWING SEAN MOVING A FAIR DISTANCE TO THE NORTHWESTOF BERMUDA. THE LATEST GFS/ECMWF MODELS CAME IN VERY CLOSE TO THEPREVIOUS NHC FORECAST...AND ONLY SMALL CHANGES WERE MADE TO THE NEWNHC TRACK. ALL OF THE GLOBAL MODELS SHOW SEAN BECOMINGEXTRATROPICAL IN TWO DAYS...AND THEN BEING ABSORBED BY A FRONTALBOUNDARY BY DAY 3.

RAINFALL...SEAN IS EXPECTED TO PRODUCE 1 TO 3 INCHES OF RAIN ONBERMUDA.

SURF...SWELLS GENERATED BY SEAN ARE AFFECTING PORTIONS OF THESOUTHEASTERN COAST OF THE UNITED STATES AND BERMUDA...CAUSINGLIFE-THREATENING SURF AND RIP CURRENTS. PLEASE SEE STATEMENTS FROMYOUR LOCAL NATIONAL WEATHER SERVICE OFFICE FOR MORE DETAILS.